The global demand for freshwater is growing rapidly. Many conventional sources of freshwater, including lakes, rivers, and aquifers, are rapidly becoming depleted. As a consequence, freshwater is becoming a limited resource in many regions. In fact, the United Nations estimates two-thirds of the world's population could be living in water stressed regions by 2025.
Currently, approximately 97% of the world's water supply is present as seawater. Desalination—the process by which salinated water (e.g., seawater) is converted to fresh water—offers the potential to provide dependable supplies of freshwater suitable for human consumption or irrigation. Unfortunately, existing desalination processes, including distillation and reverse osmosis, require both large amounts of energy and specialized, expensive infrastructure. As a consequence, desalination is currently expensive compared to most conventional sources of water, and often prohibitively expensive in developing regions of the world. Therefore, only a small fraction of total human water use is currently satisfied by desalination. More energy efficient methods for water desalination offer the potential to address the increasing demands for freshwater, particularly in water stressed regions.